In an integrated circuit having a flyback switching regulator topology, an external transformer is coupled to the integrated circuit to provide a direct current to direct current (DC-to-DC) isolated power supply to attached circuitry. Typically, a primary winding of the transformer may be coupled to a transistor that is controlled by an output pin of the integrated circuit to activate the external transformer. The transformer may produce an inductive voltage, sometimes referred to as an inductive voltage kick, when the transistor is shut off, for example. The inductive voltage kick is generated due to the change in current of the inductive winding of the transformer, since the inductive winding tends to oppose current change. The inductive winding of the transformer continues to drive current, even when the voltage supply to the inductive winding is removed. The inductive voltage kick may cause the voltage level to exceed a voltage rating of the transistor.
Generally, an integrated circuit device may include components to prevent such an inductive voltage kick from exceeding a safe voltage level for the transistor. For example, a snubber circuit may be utilized to provide a level of voltage protection for the transistor. A typical snubber circuit is implemented using external, discrete circuit components. However, if the snubber circuit is external to the integrated circuit device, the connection pins that couple the snubber circuit to the integrated circuit device may expose the integrated circuit device to electrostatic discharge (ESD) events during manufacture, assembly, and handling. Adding ESD protection components may add additional costs and complexity.
Therefore, there is a need for an integrated circuit device that has enhanced protection against power events, such as ESD and inductive voltage events.